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S Nov 10, 2016 at 14:16 history suggested Loreno Heer CC BY-SA 3.0
added missing in to the title
Nov 10, 2016 at 13:56 review Suggested edits
S Nov 10, 2016 at 14:16
Sep 10, 2016 at 14:43 comment added Sergei Akbarov @LSpice, excuse me, I did not understand from the very beginning, what the question is about, and besides this I forgot to write another condition: $1\in X$.
Sep 10, 2016 at 13:24 comment added LSpice @SergeiAkbarov, probably I misunderstand, but minimal in what sense? If in the sense of set containment, then replacing $\mathbb N$ by its subset of successors seems to contradict its minimality.
Sep 10, 2016 at 13:14 vote accept CommunityBot
Sep 10, 2016 at 12:53 answer added Sidney Raffer timeline score: 35
Sep 10, 2016 at 9:56 answer added Wojowu timeline score: 23
Sep 10, 2016 at 9:52 comment added Sergei Akbarov Ah, excuse me, I did not understand the question!
Sep 10, 2016 at 9:50 comment added Wojowu @SergeiAkbarov This is not a first-order definition.
Sep 10, 2016 at 9:50 comment added Sergei Akbarov Why don't you want to define $\mathbb N$ as a minimal subset $X$ in $\mathbb Z$ with the property $x\in X\ \Rightarrow\ x+1\in X$?
Sep 10, 2016 at 9:46 comment added KConrad Is this just asked out of curiosity, or do you have a problem with this use of the four-square theorem? I always regarded this approach as illustrating that the result (definability of $\mathbf N$ within $\mathbf Z$) has real substance to it.
Sep 10, 2016 at 9:09 history asked user40023 CC BY-SA 3.0